1990 blue water Pro am skier surging

Bdenes

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Aug 17, 2017
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I have an issue at 2800 rpm missing and backfire intermittent. I have changed the fuel pump new inline filter, plugs, wires,distributor cap and rotor and a rebuilt carburetor and even pulled the gas tank to check for stuff in it. Any thoughts on what to look at next? Or just take it in to the shop?
 

alldodge

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Howdy

Nice to know you have a boat, but we really need to know what motor you have?
Does it do it only at 2800, what about higher rpms?
Is this a new to you boat or is this just a new issue?

new inline filter

What kind of filter and do you have a canister filter?
 

Bdenes

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Aug 17, 2017
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My bad Chevy 5.7L 260 hp inboard I have owned it new 1990 it's a new problem inline fram 3/8 I think it's #4 I added it with the rest of the new
parts the distributor is after market delco electronic put in 1992
 

Rick Stephens

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Aug 13, 2013
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First thing I would think is carburetor. Does the splutter hit whether you're pulling or cruising?

Carburetor rebuilds that miss the problem is probably the number one repair that needs to be redone. Not picking on your mechanical skills, not at all. That is just one of those jobs........ use a piece of wire or fishing line or welding tip cleaner and run the ports to make for sure and for certain they are all open and clean. Double check every measurement of float height, linkage bends and so on. Gotta be perfect. Also look careful to make sure the throttle plate shaft hoes aren't wearing open. Ski boats tend to run the same throttle position all the time and the shaft can wear a spot on the housing that leaks.

Everyone is going to tell you not to use automotive fuel filters, so might as well start that ball rolling. Automotive inline filters not only unsafe but illegal in a boat. You want and really need a spin on marine canister filter with water separator capability. Take out the automotive filters and make sure to use only marine rated fuel line.

Double check timing. You should see around 24-26? advance when you spin up past 2k. Make sure the advance is working correctly.
 

alldodge

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Does it do it only at 2800, what about higher rpms?

If it continues to do it above 2800 then its not getting enough gas and running lean. If it does it only at 2800 then which carb do you have?
 

Bdenes

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Aug 17, 2017
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In regards to the carberator I paid $250 to rebuilder so I did not go into any detail work you have suggested its Rochester 650cfm so I will correct my. Filter issue
Before a I ran with no filter of any kind for 25 years. I will check the timing I was thinking that. It might be the timing not advancing property. I will work on it Thursday Update then thank you for the tips. It seems to run better over 3100rpm it also starts easy runs good lower rpm
 

kenny nunez

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Jun 20, 2017
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I see that you installed a GM HEI distributor in 92 . If your original distributor was also electronic why did you change it ? If you look on a auto that has HEI you will notice that the wire that powers it is larger than the the one that powered the coil on your older system. It may be worth a try to rig up a heavy jumper wire to the HEI and see if that helps, If it does then get e 30 amp power relay to power it up to take the load off the current ignition feed.
 

Bdenes

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Aug 17, 2017
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It came with a Mallory dual point issues all the time that's why I changed it in 1992 it maybe the carburetor is done and time for a new one
if there is worn parts in it! Again thank all of you for the input!
 

kenny nunez

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Be sure to to check the voltage to the HEI while the engine is running. It should be at least 12 or 13 volts to properly power the ignition.
 
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